Arrangement for radio-telephone traffic through exchange between mobile stations andbetween such stations and a telephone network



k, May 23,1950

F. LANG ARRANGEMENT FOR RADIO-TELEPHONE TRAFFIC THROUGH EXCHANGE BETWEENMOBILE STATIONS AND BETWEEN SUCH STATIONS AND A TELEPHONE NETWORK FiledMarch 16, 1948 PM)? La) Patented May 23, 1950 UNITED STATES OEHHUFI [\UUPATENT OFFICE Fritz Ling, Solothurn, Switzerland, assignor to AutophonAktiengesellschatt, Solothurn, Switzerland Application March 16, 1948,Serial No. 15,216 In Switzerland March 19,1941

3 Claims. 1

In order to enable radio-telephone communication between mobile stationsand a stationary station, each mobile station and the stationary stationare provided with a transmitter and a receiver. Transmitter and receiverof a station may operate on the same or on different wave-lengths. Inthe case of the same wavelength, only alternate two-way traflic ispossible between two stations, 1. e. the transmitter and the receiveroperate alternately, the switching over to transmission or to receptionhas to be effected in both co-operating stations. Automatic traflicthrough a telephone network, for example, is then not possible.

For every direct automatic trafllo, two diflerent wave-lengths for thetransmitter and the receiver are necessary. In the case of a grou ofmobile stations which all possess the same pair of wave-lengths andwhich have to be all in communication with a stationary station, suchcommunication with the stationary station is possible by way of two-wayor duplex traffic. In the case of two-way traflic the switch-over tothe-transmitter onto the receiver is effected in the mobile stationswhich possess for this purpose a, switching organ. The stationarystation may, in this case, also serve as a relay station for traificbetween two mobile stations. Duplex trafllc is only possible between amobile and a stationary station, the stationary station being howeverable to work through a telephone network.

Should duplex trafllc be possible between mobile stations, the twomobile stations have to operate on two pairs of different wave-lengthsand a transmitter-receiver pair corresponds in the stationary station toeachmobile station. If an installation comprises many mobile stations,they are advantageously divided into groups, each group operating on afixed pair of wave-lengths, a pair of transmitters and receivers beingattributed in the stationary station to each group. In such anarrangement only two mobile stations of different groups may communicatewith each other over the stationary station, the trafflc being of theduplex type, which is more convenient and more simple than alternatetwo-way traiiic. But this arrangement possesses, however, thedisadvantage that mobile stations of the same group are unable tocommunicate with one another.

The object of the present invention is to enable an all-round trafficbetween mobile stations over a stationary station as a relay, as well asbetween the mobile stations and the subscribers of a network. It relatesto an arrangement for radio-telephone traflic over an exchange, themobile stations each comprising a radio transmitter and receiver withdifferent fixed wavelengths, such stations being divided into groups toeach group being allocated a pair of wavelengths as well as atransmitter and a receiver in the exchange, and the arrangement ischaracterised in that the exchange, the receiver and the transmitter areinterconnected and connected to the automatic exchange in such a manneras to enable a two-way traflic between mobile stations of the same groupand a duplex trafllc between mobile stations of different groups, aswell as between mobile stations and stations of the telephone network.In case of two-way trafilc the receivers remain permanently in operationand only the transmitter of a mobile station is being cut-off duringlistening to a cooperating station. In order to enable this, each mobilestation comprises a switching organ. The exchange possesses, apart fromthe transmitter and receiver pairs attributed to each group, anautomatic telephone exchange and trafllc transmission between the mobilestations or between mobile stations and the network may be effectedautomatically in the exchange.

The invention is described by way of example with reference to theaccompanying drawing, wherein Fig. 1 is a diagrammatic view of theradio-telephone arrangement of the invention, and Fig. 2 is adiagrammatic view in greater detail of one of the transmitter stations.The drawing illustrates mobile stations subdivided into groups, theexchange with the transmitters and receivers and the variouspossibilities of communication. The subscriber groups of the mobilestations are designated by I and II. Group I comprises subscribers A, BK. Group 11 comprises subscribers L, M P. Each station comprises atransmitter S and a receiver E and in each group I the wave-length l isattributed to each transmitter and the wave-length 2 to each receiver,in group II the wave-length 3 is attributed to each transmitter, and thewavelength l to each receiver. The mobile subscribers being subdividedinto two groups. the

exchange comprises two transmitters and two receivers, more particularlyreceiver En with wave-length i and the transmitter Sn with wavelength 2for group I and receiver E, with wavelength 3 and a transmitter S24 withwave-length I for group II. Apart from that, the exchange Z comprises anautomatic exchange of a standard telephone network, with which themobile stations may communicate.

The trafllc between the stations is effected as follows: should themobile subscriber A, for example, wish to communicate with the mobilesubscriber L, then the transmitter Sn cooperates with the receiver En inthe exchange, this receiver being connected to the transmitter Sncooperating with the receiver Eu of the mobile station L. Also, thetransmitter S13 cooperates with the receiver En which is connected tothe transmitter Sn cooperating with the receiver En of the station A.The traflic is of the duplex transmission type. The connection of thetransmitters and of the receivers in the exchange may be effected eithermanually or automatically. In the present example, the installationcomprises two subscriber groups. It is clear that the installation maycomprise any number of groups and that there is a number of transmitterand receiver pairs in the exchange equal to the number of subscribergroups. If the-mobile subscriber A wishes to communicate with a stationof the telephone network, the receiver E21 and the transmitter Sn, withwhich the mobile subscriber A cooperates, are switched in the exchangeover a forked connection to the automatic exchange T2 of the telephonenetwork in which the connection with the required subscriber isestablished. If the mobile subscriber A wishes, for example, tocommunicate with the mobile subscriber B, who belongs to the same group,the transmitter Sn cooperates with the receiver En which is connected tothe transmitter Sn cooperating with the receiver Ebz. Now, the traflicis of the two-way type, because when the transmitter Sn cooperates withthe transmitter Sn over the receiver En, the transmitter Sm which alsomay cooperate with the receiver En should be inoperative in order toguarantee the reception of station Sn. If the station B wishes to reply,then the transmitter Sm cooperates with receiver E11 and the lattercooperates with the receiver En over the transmitter Sn. The transmitterSn has then to be cut oil, in order to guarantee the reception ofstation Sm by the receiver En.

If such an installation comprises many mobile subscribers and severalgroups, the frequency of communications between two stations of the samegroup is small, thus the cumbersome two-way trafllc between suchstations is not of much importance. tion enables a duplex traflicbetween each mobile subscriber and all other mobile stations. Theconnected subscribers are not in a position to know forthwith whetherduplex trafllc between two mobile stations is possible or two-waytrafllc is necessary. It is possible, for example, to attribute to thesubscriber groups reference numbers which precede the subscribernumbers, in such a manner that the subscribers are notified whether theycommunicate with a subscriber of the same or of another group.Practically, duplex trafflc is effected in most cases and no furthermeasures are necessary for controlling the direction of thecommunication. In case of a connection within a group the subscribernotices when listening to On the other hand, such an installaco thecooperating station whether he is able to receive such station, or theexchange is being reached by its own transmitter, the correspondingsubscriber then cutting oiI its own transmitter when listening to thecooperating station, which produces a faultless reception of thecooperating station. The own transmitter has always to be cut-in whenspeaking.

Such a cut-in or cut-off of the own transmitter may be effected, forexample, if the microtelephone of the subscriber station comprises acommunication key with a working contact for cutting-in its owntransmitter, which contact has to be closed at least when speaking. Fig.2 shows such a working contact w in connection with the transmitter of amobile station, for example the transmitter Sls. This transmittercomprises a high-frequency element h to which is connected themicrophone m and the antenna a, and the power supply p which may beconnected to the high-frequency element h through the working contact w.The conversation key It is mechanically connected to the working contact20. When the conversation key It is operated by the subscriber, themovement of the conversation key 1c is transferred to the workingcontact w, so that the connection between power supply and thehigh-frequency element is established, whereby the transmittingcondition of the transmitter is established. Ii duplex transmission ispossible,

the contact may remain closed, also when listening, 1. e. through thewhole duration of the communication. In case of two-way traflic, thereception of the cooperating station by the .sub-

scriber will be unsatisfactory or not possible at all and the key willhave to be released, which makes the own transmitter inoperative andreception of the cooperating station being made possible. But theinstallation may also be such that instead of a microtelephone key acommunication key with an idle contact is provided, over which the owntransmitter of the station is permanently cut-in during a communication.In the case of two-way traflic, and if the reception of the cooperatingstation by the subscriber is unsatisfactory or impossible, he may, whenlistening, cut-oil by means of this switch its own transmitter and outit in again when speaking. In the case of duplex tramc this switch hasnot to be operated.

What I claim is:

In an arrangement for radio-telephone traf- ,-iic, mobile stationsarranged in groups, an exchange and a telephone network" forestablishing two-way trafflc between the mobile stations of the samegroup, as well as a simultaneous two-way t afllc connection between themobile stations of different groups, as well as between the mobilestations and the stations of the telephone network, said mobile stationscomprising each a transmitter and a receiver, to each of saidtransmitter and receiver being attributed a transmitting and receivingwavelength respectively, the transmitting and receiving wavelengths ofamobile station being different, but all transmitting wavelengths inthemselves and all receiving wavelengths in themselves being equalwithin the same group, but different in diiIerent groups, and in eachexchange one each a transmitter and a receiver for each group, saidtransmitter and receiver of the exchange being interconnected andconnected with said telephone network.

' 2. In an arrangement according to claim 1, microtelephones in saidmobile stations, in said microtelephones one each a conversation key anda working contact for cutting-in the associa 7 transmitter duringtwo-way trafllc.

3. In an arrangement according to claim 1, a conversation key with anidle contact for permanent cut-in of the transmitter of a mobile stationduring simultaneous two-way traflic and for outting-out the saidtransmitter when listening to the cooperating station in alternatetwo-way trafiic.

FRITZ LANG.

REFERENCES CITED The following references are of record in the file ofthis patent:

6 UNITED STATES PATENTS Number Name Date Fox Nov. 24, 1936 Green et a1.Dec. 22, 1936 Tidd Dec. 22, 1936 Bishop et a1. Dec. '7, 1938 MastiniSept. 6, 1938 Knotts Feb. '7, 1939 Haigis Aug. 4, 1942 Hersey June 11,1946 Deloraine May 27, 1947

